Quantum monte carlo study of the energetics of small hydrogenated and fluoride lithium clusters

• Published in: Journal of computational chemistry Vol. 37; no. 17; pp. 1531 - 1536
• Main Authors: Moreira, N. L., Brito, B. G. A., Rabelo, J. N. Teixeira, Cândido, Ladir
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 30.06.2016; Wiley Subscription Services, Inc
• Subjects: binding energy; doped lithium clusters; electron correlation energy; Electrons; Fluorides; Lithium; Monte Carlo simulation; quantum Monte Carlo; Quantum physics; doped lithium clusters; quantum Monte Carlo; electron correlation energy; binding energy
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.24363

An investigation of the energetics of small lithium clusters doped either with a hydrogen or with a fluorine atom as a function of the number of lithium atoms using fixed‐node diffusion quantum Monte Carlo (DMC) simulation is reported. It is found that the binding energy (BE) for the doped clusters increases in absolute values leading to a more stable system than for the pure ones in excellent agreement with available experimental measurements. The BE increases for pure, remains almost constant for hydrogenated, and decreases rapidly toward the bulk lithium for the fluoride as a function of the number of lithium atoms in the clusters. The BE, dissociation energy as well as the second difference in energy display a pronounced odd–even oscillation with the number of lithium atoms. The electron correlation inverts the odd–even oscillation pattern for the doped in comparison with the pure clusters and has an impact of 29%–83% to the BE being higher in the pure cluster followed by the hydrogenated and then by the fluoride. The dissociation energy and the second difference in energy indicate that the doped cluster Li3H is the most stable whereas among the pure ones the more stable are Li2, Li4, and Li6. The electron correlation energy is crucial for the stabilization of Li3H. © 2016 Wiley Periodicals, Inc. Lithium clusters attract great attention due to their simplicity and potential to technological applications. Although considered simple they are still a challenge for theorists and experimentalists. A major issue in this respect is the energetics and stability of these systems and their dependence on the charge distribution in the cluster formation. This article uses accurate methods to date to discuss the energetics and electron correlation effects in small doped lithium clusters with hydrogen and fluorine atoms.